Jim, I don't know if you are planning to use a slider or not but I use a standard Brodak offset pad, which seems to do the job for me. As for the tank size, 4 ounces will not be enough as you perfect your low speed performance. The position of the tank is your choice but if this is your first foray into profile carrier I would put the tank outboard until your skill sets improve. KISS is the word for starting out. Hope this helps.
Wayne

The problem you will encounter with an inboard mounted tank is that the engine will go rich in the air because centrifugal force will want to sling the fuel towards the outside of the circle. Imagine if the tank was a foot above the engine-same idea. If you try to compensate with a lean needle setting, you will in all probability be too lean to get off the ground without quitting. (If you weren't trying to leap into the air at full throttle in 20 feet, you could gradually ease into the air and make it work.) If you look at pictures of carrier planes with big inboard tanks, you will see they also have a small tank on the outboard side. This tank is positioned to achieve proper fuel system geometry to make the engine happy, and the big tank feeds the little tank. This system has more potential for difficulty than a single tank, so I tend to avoid it. If it was properly vented, you could mount a typical 1" x2" x4" metal tank sideways through the fuselage between the engine bearers.

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